The invention is based on a process for diagnosing the functional elements of an internal combustion engine.
It is well known that when running internal combustion engines, the performance of the engine is influenced by varying the inlet/outlet valve control and/or varying the suction pipe or suction tract geometry. In this situation the control of the inlet/outlet valve is by one of two actuator options e.g. by means of the camshaft action, or, the control of the inlet-/outlet valve is continuous, as for example in electrochemical or electrohydraulic actuating devices of the inlet/outlet valve control. Prime examples to be mentioned here are DE 32 47 916 (device for controlling the valves of an internal combustion engine via a camshaft) and DE-PS 21 01 761. By varying the suction pipe or suction tract geometry, the tuned intake pressure charging of the combustion chambers is optimised in the current operational state of the engine, through which an increased air supply to the combustion chambers is made possible, while the position of the other actuators, in particular of the throttle valve, is otherwise unchanged. DE 36 08 310 A1 and DE 39 08 475 A1 can be cited as examples. In this case too the variations take place either discontinuously, e.g. by operating tuning valves in the suction pipe or suction tract, or the variations occur continuously through the operation of several actuator options of one or several actuators.
Furthermore, from European Patent Application EP-A 170 018 a process is known for the self-diagnosis of an actuator of an idling filling control for internal combustion engines. There, an arbitrary actuator triggering is used for the diagnosis of the actuator, i.e. instead of the triggering of the actuators to be diagnosed, which optimises the other working sequences, one or several defined actuator triggerings take place and their effects on other operational data of the internal combustion engine are analyzed. Diagnosis can thus take place only during certain operational states, in particular stationary conditions, since otherwise the engine's method of operation, in accordance with the program, i.e. optimised by further actuators, would be disturbed in its running.